This invention relates to an industrial furnace where the burner is supported by a burner block mounted in a wall of the furnace. Such walls have been either hard wall or soft wall. In either case, the furnace includes a metal shell but, in the case of a hard wall furnace, the shell is lined with insulating brick and hard brick, both made of a refractory material, while the lining for a soft wall construction includes a refractory blanket which may be used alone with the shell or may replace the hard brick and used with the shell and the insulating brick.
Soft shell linings have the advantage of better insulating characteristics but the nature of the blanket used in soft wall linings provides very little support for the burner block. If the burner block is mounted in the side wall of a furnace using a hard wall lining, the lining basically will support the burner block but, even with a hard wall lining, the burner block is not supported well if it is mounted on the top wall of the furnace.
Ideally, these difficulties could be overcome if the burner block assembly were mounted on the furnace shell. This, however, has not been practical for a number of reasons. The main reason for these difficulties is that the burner block is made of a refractory material and its support or holder is made of a metal such as stainless steel. These two materials have quite different ratios of thermal expansion so that the heat of the furnace destroys the integrity of the burner block assembly. Moreover, the metal of the holder becomes ineffective as a support at temperatures well below the desired operating temperatures of the furnace.